package com.ruoshui.core.util;

import java.io.Serializable;

public class PageUtil implements Serializable {

    private static final long serialVersionUID = 1L;

    private static Integer DEFAULT_MAX_COUNT = 5000;

    // 当前页码
    private Integer pageNum = 1;
    // 分页条数
    private Integer pageSize = 20;

    public Integer getPageNum() {
        return pageNum;
    }

    public void setPageNum(Integer pageNum) {
        this.pageNum = pageNum;
    }

    public Integer getPageSize() {
        return pageSize;
    }

    public void setPageSize(Integer pageSize) {
        this.pageSize = pageSize;
        if (this.pageSize > 0) {
            this.pageSize = this.pageSize > DEFAULT_MAX_COUNT ? DEFAULT_MAX_COUNT : this.pageSize;
        } else {
            this.pageSize = 20;
        }
    }

    public PageUtil(Integer pageNum, Integer pageSize) {
        this.pageNum = pageNum;
        this.pageSize = pageSize;
        if (this.pageSize > 0) {
            this.pageSize = this.pageSize > DEFAULT_MAX_COUNT ? DEFAULT_MAX_COUNT : this.pageSize;
        } else {
            this.pageSize = 20;
        }
    }

    public Integer getOffset() {
        pageSize = pageSize == null ? 20 : pageSize;
        pageNum = pageNum == null ? 1 : pageNum;
        int offset = pageNum > 0 ? (pageNum - 1) * pageSize : 0;
        return offset;
    }
}
